The present invention relates to drills, and more particularly to a drill which includes a disposable and/or indexable insert blade forming the tip thereof.
Disposable inserts have been known in the machine tool field for many years, and enjoy considerable popularity due to their relatively low cost and further due to the fact that they allow cutter edges to be replaced quickly and easily without the need for removing or sharpening an entire tool.
The design of tool holders for replaceable inserts calls for a considerable degree of expertise since it is necessary for the inserts to be held securely, yet be easily removable. Further, particularly in the case of inserts formed from sintered tungsten carbide, a substantially rigid support and a seat must be provided the insert so that it will not tend to flex and crack in use. The problems of design are compounded when an indexable, i.e., symmetrical, insert is to be used since this places additional constraints upon the size and shape of the insert. Accordingly, considerable effort has been expended in the design of holders for replaceable inserts.
Most cutting tools designed to date for use with disposable and/or indexable inserts have been relatively massive, thereby affording the strength and rigidity necessary to support an insert and maintain its location. For instance, U.S. Pat. Nos. 3,646,650-Milewski and 3,293,727-Simms relate to cutting tools which are relatively massive and which accept replaceable inserts. While the holders disclosed in the foregoing patents are meritorious, they do not lend themselves to the relatively slender, elongate configuration necessary for a drill. Further, none of the prior art designs is adaptable for use as a drill having disposable, indexable tips. Accordingly, it will be seen that it would be advantageous to provide a drill including an easily releasable, securely supported indexable tip.
It is therefore an object of the present invention to provide a drill having a disposable tip member.
Another object is to provide a drill having a readily indexable tip.
It is another object of the present invention to provide an inexpensively manufactured drill body which securely receives an indexable tip and conducts coolant to the working surfaces thereof.
Another object of the invention is to provide an indexable insert for use in drilling operations.
Yet another object is to provide an improved indexable insert which may be readily located in a drill body.